Historically the commercially available computer software for the display and analysis of flow cytometry data has left a great deal to be desired. This has prompted numerous individuals to write their own software to meet their own needs. Since there are many different data file formats for flow data there has always been a need to test this software on at least a subset of data file types the individual software developer intends to support. Although there has been a standard file format for flow data since 1984, it has only achieved wide spread acceptance in the last 5 years or so. Also, even though most of the manufacturers of flow cytometers have adopted the "standard" there is actually considerable variation in its implementation. Therefore, the need for a broadbased collection of data file formats against which software can be tested is still a pressing issue. From this perspective, it was proposed by Dave Coder and Eric Martz that an internet based d ata file repository be established. Furthermore, it seemed appropriate that the NFCR host this data base. Accordingly a repository was established at the NFCR utilizing the "gopher server" available through the Los Alamos National Lab's computer network. Flow cytometrists at large are free to contribute data files for the repository (although they will be screened for suitability prior to inclusion). Criteria for inclusion will be based on uniqueness: the files need to be representative of files from a particular type of flow cytometer, or they must contain a useful data set which others would find to be of interest (such as a good example of staining for BrdU {bromodeoxyuridine} incorporation or multi-color immunofluorescence). At present only about 20 files have been deposited but this is expected to grow considerably. At the present time, the Data Repository has been off-line due to security-imposed reconfiguration of the Laboratory network. GRANT NUMBER: 5P41RR01315-17 (07/01/98-06/30/99) Page 50